Is It Possible to Short A Bass Preamp with Phantom Power?

This is my first post, so I hope I've made it to the right forum- apologies if I've misplaced this.

I recently installed an EMG BQC preamp and two EMG pickups (40DCX in the neck 40JX in the bridge) in a bass for a friend. Tested everything on my amp at home, sounded great, no problems. I was actually a little upset that I couldn't just keep the thing.

I left it in our teaching studio for him and when I returned later that evening to see if he was happy with how everything came out, he claimed there was no signal coming from the bass. No wiring, etc had changed in that time, and when I opened it up, everything was in its right place. Since we have a small room in a rental office complex, the only real "amp" we have at our disposal is a small four channel mixer running into a set of desktop computer speakers (don't want to upset the neighbors- lawyers, CPA's, etc). While testing, the friend noted that he'd left phantom power turned on, on the mixer.

Since I can't think of any other variables in play- is it possible to destroy a preamp with phantom power from a mixer? I know the BQC's are only meant to take 9-27V and the mixer feeds 48v.